The phrase "most saturnalian" typically means the most wild or unrestrained, often in reference to partying or reckless behavior. Some antonyms or opposite words that could be used to describe the opposite of this behavior might include "restrained," "controlled," "sober," "reserved," "moderate," "polite," or "respectful." These terms would imply a sense of moderation or propriety, rather than the wild abandon implied by the term "most saturnalian." Depending on the context, other antonyms might include "serious," "calm," "temperate," "reserved," or "curbed," all suggesting a more responsible or less hedonistic approach to life.